Jack can run at a pace of 5mph. Jill can run at a pace of 3mph. If the started running at the same time, and they ran in a straight line in opposite directions, about how long would it take them to get 2 miles apart from each other?

They are running in opposite directions so the distance between them depends on the sum of their speeds:

so t is 1/4 hour or 15min

Two cars leave towns 230 km apart at the same time, traveling towards one another. One car travels 15 km slower than the other. They meet 2 hours later. What are their speeds?

Call the faster cars rate V, then the slower car travels V-15 km/hr

together they travel 2V-15 km/hr
so...




and simplifying we get V=65 km/hr
(and so the slower car travels 50 km/hr)

:)